The price of basic food items could rise by as much as five per cent this year
because of miserable weather last autumn, the managing director of Waitrose
has warned.

Mark Price said food price inflation is already hovering at three to three and a half per cent, but this is just "the tip of the iceberg" and prices could increase even more dramatically over the coming months.

Produce such as bread and vegetables will become up to five per cent more expensive because of poor crop yields leading to a shortage of supply, he warned.

Many farmers are reporting that they still have not planted crops for 2013 because of the torrential rainfall which caused flooding across parts of Britain late last year.

Figures released by the Met Office on Thursday showed that 2012 was the second wettest since records began in 1910, with the bulk of the rain arriving during the second half of the year.

Mr Price told Sun City the increases for some commodities would be "massive" as a result of poor crop yields, adding: "It's bread, vegetables, all produce.

"The apple crop was down 20 to 30 per cent so apple prices have to go up. You have only seen the tip of the iceberg".

Nielsen, the market research firm, claimed the true figure across all supermarkets could be even greater because inflation at Waitrose is currently lower than average.

Food price inflation in Britain was 4.6 per cent in November, analysts said, meaning that an anticipated rise of five per cent at Waitrose would translate to more than six per cent across the market as a whole.

Mr Price's comments echoed those of Sir John Beddington, the government's chief scientist, who last week warned that inflation in food prices "is not going to stop".

Speaking on the BBC's World at One, he said the growing world population and predicted increase in extreme weather would increase demand for food and make global markets more volatile.

He said: "There is going to be another billion people on the planet in 13 years’ time. There is already a billion people in poverty. That is going to increase demand for food.

“We have got climate change. We have got major changes in weather patterns, so supply is going to be extremely fragile, reserves are way down … and we are going to have these shocks.”

Mr Price was speaking as Waitrose announced a growth in sales of 5.4 per cent over the Christmas period, and told shareholders it was expanding its market share.

The Waitrose boss said the supermarket had been able to win customers from Sainsbury's last month by competing on price, claiming that it was now cheaper than its rival on a range of more than 8,000 products.

He added that sales of fresh food, champagne and party food in particular had driven the improvement in sales during the second half of December as customers prepared to entertain guests.

Analysts say the growth figures announced by Waitrose are likely to exceed those of the country's biggest supermarket chains Tesco, Asda, Sainsbury and Wm Morrison.

Waitrose's market share of 4.5 per cent is much lower than the "big four", for example Tesco which has a share of 30.7 per cent, but the chain opened 18 new shops last year bringing its total to 288.

Morrison will be the first listed supermarket to unveil its Christmas trading figures this week, with analysts expecting a like-for-like fall of more than 2.5 per cent on last year.